Rotary brush sections



y 1959 G. E. HARTWELL ETAL 2,885,706

ROTARY BRUSH SECTIONS Filed Feb. 17, 1956 M- JOSLPH V 411%??? Rs owes: r. HA2 mm. 7 BY w v a I ROTARY BRUSH SECTIONS George'E. Hartwell and Joseph V. Mertes, Catonsville, Md., assignors to Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania Application February 17, 1956, Serial No. 566,148

Claims. (Cl. 15-179) This invention relates to brushes and it has particular relation to rotary power driven brushes comprising one or more disc-like sections having radial bristles clamped between a pair of face discs which are adapted to be mounted upon a mandrel or arbor.

In the construction 'of rotary power driven brushes, it is customary to loop fibrous bristle stock, such as Tampico, wire, or the like, about a central core ring and to clamp the looped portions between side plates comprising discs' or annular rings which may be formed by stamping them from sheet metal, such as sheet steel. These discs are also provided with teeth struck at right angles to the planes of the rings and being thrust through the layer of bristle stock so that the edges thereof engage the outer perimeter of the core ring to hold the latter in place. The teeth also function to prevent the bristle stock from migrating around the core during the course of service and they clamp the annular rings in fixed position upon the layer of bristle material, this being accomplished as by clinching the ends of the teeth over upon small bunches of bristle stock. These bunches act as keys holding the rings in place by preventing the teeth from being retracted from the layer. It is to be understood that the ends of the teeth of one disc may register with the openings formed in the other plate by the striking of the teeth thereof. Therefore, the clinched ends of the teeth may be unattractive, a situation which from the standpoint of esthetics, is analogous to nails driven through a piece of timber and having their exposed points clinched over to provide a lock preventing the nails from being withdrawn. Such clinched ends, although they are highly effective in securing the nails, seldom look attractive.

- In brush construction, the edges of the plates or discs and the teeth constituting the stampings are often relatively sharp or raw and may even have burs projecting beyond the body of the metal, thus providing knife'like edges. These raw edges and burs constitute sharp angles against which the bristles are flexed in service and they may tend actually to cut the bristles. In any event, by reason of the sharp flexing or cutting action, premature bristle failure is likely to occur in service.

Inaccordance with the provisions of the present invention, the foregoing difiiculties are substantially reduced or eliminated by provisions of protective facing elements ofa fibrous or plastic material upon the inner faces of the side discs or plates of the annular brush structure. These discs serve in substantial measure to cover and conceal the clinched over tip portions of the teeth of the plates. The portions exposed through the openings also provide an attractive design in contrast with the metal of the plates. 1 *It is to be understood that portions of the fibrous plastic material may be crimped between the bristle material and the clinched portions of the teeth. These crimped portions prevent cutting or chafing of the bunch of bristles engaged by the clinched portions of the teeth.

At the same time, the .fibrous plastic discstor annuli Patented May 12, 195 9 prevent contact between the burs or edges of the annular rings constituting the side plates.

As a still further feature, the invention may comprise electrolytic treatment of the side plates having the teeth in order selectively to erode, or to etch away the thin sharp edges formed by the burs previously referred to.

For a better understanding of the invention reference may now be had to the accompanying drawings in which: Fig. 1 is a view partially in elevation and partially in phantom of a brush section constructed in accordance with the provisions of the invention; i Fig. 2 is a sectional view taken substantially upon the line II of Fig. 1;

Fig. 3 is a fragmentary detailed view illustrating one stage in the assembly of a brush in accordance with the provisions of the present invention;

Fig. 4 is a fragmentary view showng the tooth construction in a brush section which has been completed.

In the embodiment of the invention as shown in the drawings, a brush section S is indicated as comprising an annular layer of bristle material M which may be of Tampico wire or other appropriate material. Tampico treated with a tacky liquid such as menhaden, sardine oil or other oil, which stays tacky for a long time is especially useful in the brush herein disclosed. The tacky materials as disclosed in Patent 2,388,867 may successfully be employed to impregnate bristles of Tampico or other vegetable fibers used in forming the brushes of this invention. The tacky materials improve the adhesion of bufiing and abrading compounds to the bristles and they impart increased rigidity to the bristles assemblies, permitting them to be operated under relatively high pres sure of contact with the work, but at the same time, the bristles can be separated to permit them adequately to follow the contours of the work surface.

This bristle material preferably is of double length and the mid-portions thereof are looped as indicated at L about a central retaining core 10 which may be a ring of steel or other material. This ring may be of endless type or, if preferred, it may be formed by wrapping a piece of wire into a ring with or without actually joining the ends of the piece together. It will be apparent that the bristle material projects substantially radially outwardly from the ring 10.

Means clamping the bristle material in position com-. prise side plates 11 and 12. In the construction as shown, the disc 11 comprises a flat annular marginal portion indicated at 13 and a depressed central portion 14 having an arbor hole 16 formed therein. The hole, if desired, may be formed with a rim portion 17 adapted to seat upon an arbor or mandrel whereby thebrush section may be rotated by appropriate power means. The disc is further illustrated as being formed with openings 18. Air can circulate through these holes when the brush is driven and may thus produce a cooling action. If desired, the central portion 14 of the disc 11 may be omitted thus to constitute the marginal portion 13 as an annularring.

The annular ring 12 constituing the second side plate, if desired, may be replaced by a disc similar to the disc 11. However, the annular form has certain advantages inasmuch as the looped portions L of the bristles are exposed within the brush section thus permitting the free circulation of air thereabout. Obviously, when the section is mounted upon a mandrel with or without additional sections and the mandrel is rotated, the flow of air generated by the motion is substantial, thus producing cooling of the bristles. The temperature of the bristles especially about their base portions is thus maintained at a minimum and is thus conducive to maximum life of the bristles before embrittlement due to high temperatuties takesplace.

The inner .faces of the side plates or discs 12 in the embodiment of the invention shown, are provided with annuli 19 and 20 of a cushioning material, such as discs orrings of fiber, zeig. of cotton, linen, asbestos, glass, or wood pulp. These maybe employed with, or without, impregnants and binders such as rubber, phenolic resins, alkyl resins, vinylite or the like. The annuli may also be composed of plastics :such as vinylite resins, phenolic resins, rubber, or the like. These discs may be applied to theinner faces of the side plates merely by laying them inplace and the frictional pressure exerted upon the assembly by the side plates 11 and 12 may be relied upon to hold them securely in place. However, if preferred, the discs 19 and 20 may also be applied by an appropriate adhesive such as a solution of plastic. It is likewise within the purview of the invention to :apply the cushioning layers 19 and 20 as liquid layers of a hardenable material such as a hot melt, or a solution of a thermoplastic resin, or a liquid uncured-thermosetting resin. The

liquid material may be hardened merely by a cooling operation, or by a baking operation designed to cause thermosetting of theresinous material.

Means to hold the side plates 11 and 12 firmly in compression against the layer of bristle material is illustrated as comprising teeth 22 which preferably are pressed as tabs from the metal of the side plates. The shapes of the teeth preferably are elongated tongues and approximate the outline illustrated by the holes 23 shown in Fig. 1 .of the drawings. At their roots, the teeth are integral with the metal of the plates from which they are struck. The teeth are disposed.approximatelynormal with respect to the plates and the planes thereof are approximately radial with respect to the brush units.

As shown in Fig. 3, the teeth project transversely through the .stock'material S. They also pierce the inner discs .19 and 20. To facilitate the piercing of the latter, they may beprovided with holes appropriately peripherally spaced to receive the teeth; or if preferred, the tips of the teeth may merely be forced through the material constituting the discs 19 and 20. The ends of the teeth on one plate also register with the openings 23 and as shown in Fig. 4 in the finished product they are bent over orclinched as indicated at 26 in order to engage the sides ofa portion of bristle stock thus keying the teeth from retraction and locking the plates securely together.

It will be apparent that in the operation to .clinch the ends of the teeth, small portions 27 of the discs 19 and 20 are depressed and engaged or held between the clinched portions and the contiguous bristles. This is a desirable feature inasmuch as the portions under the clinched ends of the teeth provide a protective cushion which obviates or reduces the tendency of the bristles contiguous the clinched portions to chafe against the sides of the latter. The side discs or plates should be pressed toward each other with considerable force, as for example in a press in order effectively to compact the bristle material about core and between said discs or plates.

Although not specifically illustrated in the drawings, the coating of the teeth through a substantial portion of their length or even along their entire length with a plastic material such as a solution of'vinyl resin or with a phenolic resin in liquid state in order to cover up and round otr':the edges of the metal constituting the teeth is within the scope of the invention. It is likewise within the scope of the invention to apply discs 19 and to the side plates before the teeth thereof are struck. In the latter event, it is desirable that the discs 19 and 20 be secured to the metal as for example by adhesive. During the subsequent punching operation involved in cutting the teeth and bending them to appropriate angle with respect to the side plates, the-tongues of material cut in the discs 19 and 20 are retained on the :teeth and provide coatings reducing :the tendency of e the -bristles to chafe against the edge of the teeth upon the coated side. Manifestly, if

the punching operation is perform d o Pr ss the me l toward the coated side the burs and concavities providing the sharp edges of the teeth will be protected by the coatings on the teeth.

The discs, as indicated at 28, may be provided with slots adapted to receive keys non-rotatably securing the sections upon an arbor or mandrel.

The brush sections may 'be formed manually, or by apparatus recognized in the art. The method and apparatus are not particularly a part of this invention and are not described.

The brush sections maybe employed without treatment of the fibers; however, asprevionsly intimated, it is often preferred to treat them as with a tackifying agent, such as a fish oil, soya oil or other oil, which does not readily set to nontacky state. The treating operation may be performed by dipping or otherwise treating the completed sections with the liquid agent.

The sections S as thus constructed, may be mounted singly, or azplurality thereof may be strung in tandemv upon a driven mandrel or arbor. They may be used to polish or clean metal or other surfaces such as wood, stone, or the like. Buffing or abrading compounds may also be-applied to .the tips of the fibers, where they readily adhere to the latter. The work is then held .in contact with the outer perimeters of the sections S while the latter are drivenito polish, buff or grind the surface to be acted upon.

The fibers constituting the bristles in the sections S are unusually well protected by discs 19 and 20 from cutting by the sidedises 11 and Hand their teeth 22.

It has been found by experience that the construction runs unusually cool, even under heavy work loads, .80

that embrittlement of the fibers by heat is reduced to a minimum.

It is also found that the fiber discs between the side plates .11 and 12 and the bristle material enhance the appearanceof the sections.

It will be manifest to those skilled in the art that the embodiments of the invention as herein shown and described are by way of illustration. Numerous modifications may be made therein without departure from the spirit of the invention or the scope of the appended claims.

We claim:

.1. A rotary brush section comprising a pair of sidediscs of sheet metal disposedin coaxial, spaced, parallel, relationship with respect to each other, a ring constituting a core disposed'between the discs, douhled'bristles comprising fibers looped about the core and being clamped between the side discs, protectivefiber discs disposed between the side discs and the.bristles, said side discshaving teeth struck inwardly therefrom and projecting normally with respect to the discs whereby to leave openingsin the discs and being disposed in planes radial with respect to the section, the teeth being thrust through the bristles each having the tip portion thereof thrust through and clinched upon a portion of the protective disc upon the side opposite to the side disc to which the tooth is attached, the portions of the protective discs under the clinched tip portions of the teeth acting to prevent the cutting of the contiguous portions of the bristles by said clinched portions of theteeth.

2. A rotary brush section comprising a pair of annular side discs of sheet metal disposed in coaxial, spaced, parallel relationship with respect to each other, a ring constituting a core disposed between the discs, doubled bristles comprising fibers looped about the core and being clamped between the side discs, protective discs of fibrous materials disposed between side discs and bristles, the side discs having teeth struck normally inwardly therefrom: and being disposed in planes which are radial of the section, the teeth being thrust through the bristles and further having the tip portions thereof thrust through and clinched .upon portions of the protective discs upon the sides opposite the disc to which the teeth are attached, the tips of the teeth of one side disc being disposed adjacent to openings formed by striking the teeth of the other side disc, portions of the protective discs being gripped under the clinched portions of the teeth whereby to secure the side discs together and concomitantly, to obviate cutting of the bristles by the clinched portions of the teeth.

3. A rotary brush section as defined in claim 2 in which the bristles are of organic fibers.

4. A brush section as defined in claim 2 in which the bristles are of T ampico fibers.

5. A rotary brush section comprising a pair of side discs of sheet metal disposed in coaxial, spaced, parallel, relationship, a ring constituting a core between the discs, doubled bristles of Tampico fibers said bristles being;;impregnated with a tacky oil and being looped aboutthe core and clamped between the side discs, protective discs of fiber material disposed between the side discs and the bristles, teeth struck normally inwardly from the side discs and being disposed in planes radial of the section, the teeth being struck through the bristles, each tooth having the tip portion thereof thrust through and clinched upon a portion of the adjacent protective disc upon the side opposite the side disc to which the tooth is attached, the tips of the teeth of one disc being disposed adjacent openings formed by the striking of the teeth of the other, portions of the protective discs being gripped under the clinched portions of said teeth whereby to secure the side discs together and concomitantly to obviate cutting of the bristles by the clinched portions.

References Cited in the file of this patent UNITED STATES PATENTS 938,275 Riehl Oct. 26, 1909 1,817,176 Curtis Aug. 4, 1931 1,900,575 Mertes Mar. 7, 1933 2,296,949 Roberts Sept. 29, 1942 2,388,867 Peterson Nov. 13, 1945 

